Subjects with lumbar DDD who are candidates for ALIF at a single level will be screened for inclusion in the study. If the subject meets all of the eligibility criteria, they will be enrolled and randomized to either the Aspen or pedicle screw group. Subjects will continue to be followed by the guidelines set forth in this clinical protocol, which include: a postoperative discharge exam; six week, three month, six month, and one year post-op visits; and, concludes with a two year post-op visit. The follow-up is counted from the day of surgery. The enrollment period is expected to be approximately 12 months and subjects will be followed for 2 years post-op for the duration of the clinical investigation. The anticipated duration of the study is approximated to be 3 years.